Two simple decoders for Retro computing processors.

decoders/mc6809/__init__.py

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+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2026, fjkraan@electrickery.nl
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, see <http://www.gnu.org/licenses/>.
+##
+
+'''
+The Motorola MC6809 is an 8-bit microprocessor.
+
+In addition to the 8-bit data bus, this decoder requires the input signals
+E, Q, RD/WR (read-not-write) to do its work. An explicit
+clock signal is not required. 
+
+Details:
+https://ia803103.us.archive.org/14/items/mc6809mc6809e8bitmicroprocessorprogrammingmanualmotorolainc.1981/MC6809-MC6809E%208-Bit%20Microprocessor%20Programming%20Manual%20%28Motorola%20Inc.%29%201981.pdf
+https://github.com/M6809-Docs/m6809pm
+'''
+
+from .pd import Decoder

decoders/mc6809/pd.py

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+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2026, fjkraan@electrickery.nl
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 2 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, see <http://www.gnu.org/licenses/>.
+##
+## Version 1.2, 2026-01-17
+
+import sigrokdecode as srd
+from functools import reduce
+
+class Ann:
+    ADDR, MEMRD, MEMWR, INSTR, ROP, WOP, WARN = range(7)  # 0, 1, 2, 3, 4, 5, 6
+
+class Row:
+    ADDRBUS, DATABUS, INSTRUCTIONS, OPERANDS, WARNINGS = range(5)  # 0, 1, 2, 3, 4
+
+class Cycle:
+    NONE, MEMRD, MEMWR = range(3)
+
+ann_data_cycle_map = {
+    Cycle.MEMRD:  Ann.MEMRD,
+    Cycle.MEMWR:  Ann.MEMWR,
+}
+
+class Pin:
+    RW, E, Q = range(0, 3)      # 0, 1, 2
+    D0, D7 = 3, 10              # 3, 4, 5, 6, 7, 8, 9, 10
+    A0, A15 = 11, 27            # 11, 12, 13, 14, 15, 16, 17, 18,  19, 20, 21, 22, 23, 24, 25, 26
+
+def reduce_bus(bus):
+    if 0xFF in bus:
+        return None # unassigned bus channels
+    else:
+        return reduce(lambda a, b: (a << 1) | b, reversed(bus))
+
+class ChannelError(Exception):
+    pass
+
+class Decoder(srd.Decoder):
+    api_version = 3
+    id = 'mc6809'
+    name = 'MC6809'
+    longname = 'Motorola MC6809'
+    desc = 'Decoder for the Motorola MC6809 microprocessor can be loaded by sigrok.'
+    license = 'gplv2+'
+    inputs = ['logic']
+    outputs = []
+    tags = ['Retro computing']
+    channels = (
+        {'id': 'rw', 'name': 'R/W', 'desc': 'Read / not Write'},                # 0
+        {'id': 'e', 'name': 'E', 'desc': 'Bus timing / enable clock'},          # 1
+        {'id': 'q', 'name': 'Q', 'desc': 'Bus timing / quadrature clock'},      # 2
+    ) + tuple({
+        'id': 'd%d' % i,                                                        # 3-10
+        'name': 'D%d' % i,
+        'desc': 'CPU data line %d' % i
+        } for i in range(0, 8)
+    ) + tuple({
+        'id': 'a%d' % i,                                                        # 11-26
+        'name': 'A%d' % i,
+        'desc': 'CPU address line %d' % i
+        } for i in range(0, 16)
+    )
+    optional_channels = (
+        {'id': 'ba', 'name': 'BA', 'desc': 'Bus enable'},
+        {'id': 'bs', 'name': 'BS', 'desc': 'Bus status'},
+    ) + (
+        {'id': 'nmi', 'name': '/NMI', 'desc': 'not Non-Maskable Interrupt'},
+        {'id': 'irq', 'name': '/IRQ', 'desc': 'not Interrupt'},
+        {'id': 'firq', 'name': '/FIRQ', 'desc': 'not Fast Interrupt'},
+        {'id': 'dmabrq', 'name': '/DMA/BREQ', 'desc': 'not Direct Memory Access / not Bus Request'},
+        {'id': 'mrdy', 'name': 'MRDY', 'desc': 'Memory Ready'},
+        {'id': 'rst', 'name': '/RESET', 'desc': 'not Reset'},
+        {'id': 'halt', 'name': '/HALT', 'desc': 'not Halt'},
+    )
+    annotations = (
+        ('addr', 'Memory address'),           #
+        ('memrd', 'Byte read from memory'),   #
+        ('memwr', 'Byte written to memory'),  #
+        ('instr', '6809 CPU instruction'),    #
+        ('rop', 'Value of input operand'),    #
+        ('wop', 'Value of output operand'),   #
+        ('warning', 'Warning'),               #
+    )
+    annotation_rows = (
+        ('addrbus', 'Addr.', (Ann.ADDR,)),          # 0
+        ('databus', 'Data', (Ann.MEMRD, Ann.MEMWR)),  # 1
+        ('instructions', 'Instructions', (Ann.INSTR,)),   # 2
+        ('operands', 'Operands', (Ann.ROP, Ann.WOP)),     # 3
+        ('warnings', 'Warnings', (Ann.WARN,))             # 4
+    )
+
+    def __init__(self):
+        self.reset()
+
+    def reset(self):
+        self.prev_cycle = Cycle.NONE
+        self.op_state   = self.state_IDLE
+
+    def start(self):
+        self.out_ann    = self.register(srd.OUTPUT_ANN)
+        self.bus_data   = None
+        self.samplenum  = None
+        self.addr_start = None
+        self.data_start = None
+        self.dasm_start = None
+        self.pend_addr  = None
+        self.pend_data  = None
+        self.ann_data   = None
+        self.ann_dasm   = None
+        self.prev_cycle = Cycle.NONE
+        self.op_state   = self.state_IDLE
+        self.instr_len  = 0
+
+    def decode(self):
+        while True:
+            pins = self.wait()
+            cycle = Cycle.NONE
+            if pins[Pin.Q] == 1 and pins[Pin.E] == 0: # default to asserted
+                if pins[Pin.RW] == 0:
+                    cycle = Cycle.MEMWR #
+                else:
+                    cycle = Cycle.MEMRD #
+
+            if cycle != Cycle.NONE:
+                self.bus_data = reduce_bus(pins[Pin.D0:Pin.D7+1])
+            if cycle != self.prev_cycle:
+                if self.prev_cycle == Cycle.NONE:
+                    self.on_cycle_begin(reduce_bus(pins[Pin.A0:Pin.A15+1]))
+                elif cycle == Cycle.NONE:
+                    self.on_cycle_end()
+                else:
+                    self.on_cycle_trans()
+            self.prev_cycle = cycle
+
+    def state_IDLE(self):
+        self.want_dis   = 0
+        self.want_imm   = 0
+        self.want_read  = 0
+        self.want_write = 0
+        self.want_wr_be = False
+        self.op_repeat  = False
+        self.arg_dis    = 0
+        self.arg_imm    = 0
+        self.arg_read   = 0
+        self.arg_write  = 0
+        self.arg_reg    = ''
+        self.mnemonic   = ''
+        self.instr_pend = False
+        self.read_pend  = False
+        self.write_pend = False
+        self.dasm_start = self.samplenum
+        self.op_prefix  = 0
+        self.instr_len  = 0
+
+    def on_cycle_begin(self, bus_addr):
+        if self.pend_addr is not None:
+            self.put_text(self.addr_start, Ann.ADDR,
+                          '{:04X}'.format(self.pend_addr))
+        self.addr_start = self.samplenum
+        self.pend_addr  = bus_addr
+
+    def on_cycle_end(self):
+        self.instr_len += 1
+        if self.ann_dasm is not None:
+            self.put_disasm()
+        if self.op_state == self.state_RESTART:
+            self.op_state = self.state_IDLE()
+
+        if self.ann_data is not None:
+            self.put_text(self.data_start, self.ann_data,
+                          '{:02X}'.format(self.pend_data))
+        self.data_start = self.samplenum
+        self.pend_data  = self.bus_data
+        self.ann_data   = ann_data_cycle_map[self.prev_cycle]
+
+    def on_cycle_trans(self):
+        self.put_text(self.samplenum - 1, Ann.WARN,
+                      'Illegal transition between control states')
+        self.pend_addr = None
+        self.ann_data  = None
+        self.ann_dasm  = None
+
+    def state_RESTART(self):
+        return self.state_IDLE
+
+    def put_text(self, ss, ann_idx, ann_text):
+        self.put(ss, self.samplenum, self.out_ann, [ann_idx, [ann_text]])
+
+    def put_disasm(self):
+        text = formatter.format(self.mnemonic, r=self.arg_reg, d=self.arg_dis,
+                                j=self.arg_dis+self.instr_len, i=self.arg_imm,
+                                ro=self.arg_read, wo=self.arg_write)
+        self.put_text(self.dasm_start, self.ann_dasm, text)
+        self.ann_dasm   = None
+        self.dasm_start = self.samplenum

decoders/tms7000/__init__.py

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+##
+## This file is part of the libsigrokdecode project.
+##
+## Copyright (C) 2026, fjkraan@electrickery.nl
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, see <http://www.gnu.org/licenses/>.
+##
+
+'''
+The TMS7000 is an 8-bit microprocessor family. This decoder is for the MC-mode.
+
+In addition to the 8-bit data bus, this decoder requires the input signals
+/EN (enable), RD/WR (read not write) and AS (address strobe) to do its work. An explicit
+clock signal is not required. However, the TMS7000 CPU clock may be used as
+sampling clock, if applicable.
+
+Details:
+https://archive.org/details/bitsavers_tiTMS70001ataManual_33796916/mode/2up?q=tms7000+family+data  page 4-45
+'''
+
+from .pd import Decoder